Novel Motor-Kinetic-Energy-Based Power Pulsation Buffer Concept for Single-Phase-Input Electrolytic-Capacitor-Less Motor-Integrated Inverter System

The motor integration of singe-phase-supplied Variable-Speed Drives (VSDs) is prevented by the significant volume, short lifetime, and operating temperature limit of the electrolytic capacitors required to buffer the pulsating power grid. The DC-link energy storage requirement is eliminated by using the kinetic energy of the motor as a buffer. The proposed concept is called the Motor-Integrated Power Pulsation Buffer (MPPB), and a control technique and structure are detailed that meet the requirements for nominal and faulted operation with a simple reconfiguration of existing controller blocks. A 7.5 KW, motor-integrated hardware demonstrator validated the proposed MPPB concept and loss models for a scroll compressor drive used in auxiliary railway applications. The MPPB drive with a front-end CISPR 11/Class A EMI filter, PFC rectifier stage, and output-side inverter stage achieved a power density of 0.91 KW L−1 (15 W in−3). The grid-to-motor-shaft efficiency exceeded 90% for all loads over 5 kW or 66% of nominal load, with a worst-case loss penalty over a conventional system of only 17%.

Performance Analysis of Direct Torque Controllers in Five-Phase Electrical Drives

The industrial application of electric machines has grown in the last decades, thanks to the development of microprocessors and power converters, which have permitted their use as variable-speed drives. Although three-phase machines are the common trend, the interest of the research community has recently focused on machines with more than three phases, known as multiphase machines. The principal reason lies in the exploitation of their advantages in terms of reliability, i.e., post-fault operating capability. Additionally, multiphase machines provide a better current distribution among phases, and lower current harmonic production in the power converter, than conventional three-phase machines. However, multiphase drive applications require the development of complex controllers to regulate the torque (or speed) and flux of the machine. In this regard, direct torque controllers have appeared as a viable alternative due to their easy formulation and high flexibility to incorporate control objectives. However, these controllers face some peculiarities and limitations in their use that require attention. This work aims to tackle direct torque control as a viable alternative for the regulation of multiphase drives. Special attention will be paid to the development of the control technique and the expected benefits and limitations in the obtained results. Case examples based on symmetrical five-phase induction machines with distributed windings in the motoring mode of operation will be used to this end.

Direct Current (DC) Motor Speed and Direction Controller

The direct current motor is an important drive configuration for many applications across a wide range of power and speeds. It has variable characteristics and is used extensively in variable-speed drives. The goals of this project are to control the direction and speed of a Direct Current (DC) motor. Due to the advancement of wireless technology, there are several communication devices introduced such as GSM, Wi-Fi, ZIGBEE and Bluetooth. Each of the connections has its own unique specification and application. Among these wireless connections, Bluetooth technology is often implemented and can be sent from the mobile phone at a distance of 10 meters. The speed control was implemented using Bluetooth technology to provide communication access from a smartphone. Instead, the ARDUINO UNO platform can be used to quickly promote electronic systems. And an electronics technique is called Pulse Width Modulation (PWM) is used to achieve speed control, and this technique generates high and low pulses, then these pulses vary the speed in the motor. In order to control this PWM pulse, variable resistors are used and depend on it the speed of the DC motor will increase or decrease. The variable resistor is adjusting to varying the speed of the motor, and the higher the resistance the lower the speed of the motor rotates. The direction of the motor is controlled by the relay by giving and giving a command on the virtual terminal. The speed of the motor is directly proportional to the resistance as the speed increased after the resistance also increased and vice versa. The significance of this study is practical and highly feasible from the economic point of view and has the advantage of running the motor at a higher rating in term of a reliable, durable, accurate and efficient way of controlling speed and direction control.

ENERGY SAVINGS IN AUXILIARY VENTILATION SYSTEMS OF UNDERGROUND MINES

Energy is a basic need for industries around the world. In recent years, electrical power costs have risen considerably and this rise is likely to continue in the future. Meanwhile, the increasing cost of ventilating mines safely and efficiently is of vital importance. Ventilation on demand has the potential to optimize electrical consumption while maintaining the safety of mines. This paper investigates the energy efficiency enhancement through ventilation on demand in underground mines by installing variable speed drives on the auxiliary mine ventilation fans to provide variable airflow control. Variable speed drives are cost effective and manageable and require low maintenance. It has been estimated that a total electrical energy saving of 324,300 kW, or 53%, can be achieved in 1 year by using variable speed drives. Therefore, it is possible to reduce CO2 emissions by 155.6 tons per year with a simple payback period of 5 months 220 days.

A Comprehensive ESP Preventive Maintenance Program for Long-Term Reliability, Better Life Cycle and Maximum Availability

The reliability of Electrical Submersible Pumps (ESPs) is a critical target for companies managing artificially lifted fields. While efforts to continuously improve the reliability in the downhole system are crucial, it is necessary to focus on the health and long-term reliability of the ESP surface equipment. One effective approach toward achieving this goal is through conducting a comprehensive Preventive Maintenance Program (PMP) for the different components of the ESP surface system. An ESP PMP should be managed without jeopardizing production strategy. The design of the PMP must meet the production demand while maintaining the best-in-class PMP practices. The well operating condition, frequency, weather, well location, required periodic inspection and preemptive servicing and replacement of surface equipment components must be considered, based on studied criterion. The design of the PMP considers equipment upgrades and thermal imaging surveillance to guarantee healthy electrical systems. The mentioned activities have to be captured in a dedicated checklist to cover all requirements. To ensure adequate PMP planning, a well-structured tracking mechanism must be followed. Implementing the recommended PMP framework contributes to minimizing ESP surface equipment component defects like transformer failures, blown fuses, jammed fans, obsolete drive controllers, etc. The proposed PMP is structured to achieve maximum production availability while maintaining a healthier run-life of surface equipment with minimal outages. To ensure minimal ESP surface equipment malfunctions, a comprehensive periodic checkup and well-designed replacement mechanism of surface equipment components should be implemented. The operator company and the maintenance service provider will be able to easily identify the bad actors without complicating the overall process. Consequently, efforts will be made to assign and implement corrective actions to avoid similar problems. The PMP will significantly enhance the ESP surface equipment reliability and prolong the uptime of the fixed/variable speed drives, associated transformers, and other auxiliary equipment. In addition, it should reduce the ESP trips attributed to the malfunction of any surface equipment component and consequently minimize the operational and financial impact of production disruptions. Ultimately, the operator company will be able to maximize its production availability and comply with its planned strategies to meet its target. As a result, the PMP will significantly improve the ESP Key Performance Indicator(KPI) records. In this paper, an innovative and structured framework for ESP surface equipment PMP will be illustrated in details. Additionally, a prototype that contains the main formulas and tools in the program, which were derived from huge historical records and data analytics, will be shown. The paper will explain why and how the PMP can help any operator company or service provider to excel in maintaining healthy ESP systems while meeting its production commitments.

Improving Motor Performance and Runtime in ESP Applications with Novel Sinewave Filter

In recent years, the Oil and Gas Industry has greatly improved efforts in evaluating the electrical system involved in operating Electrical Submersible Pumps (ESP). The negative effects that poor power quality has on ESP motors equipped with variable speed drives is generally understood by the industry. However, with a strong focus on optimization and reliability, improvements of the power quality provided to our ESP systems has tremendous potential to enhance the ESP lifecycle. This paper will provide a detailed description of the current mitigation technique involving the conventional designs of PWM sinewave filters. Additionally, this paper will outline multiple Case Studies that have been conducted on several wells with ESPs installed, that demonstrate the success of a new design approach for PWM sinewave filters yielding lower electrical distortion and significantly improved motor performance. A detailed analysis evaluating problems and premature failures was performed on existing ESP wells equipped with both "6-step" and PWM operation. Computer simulations executed to analyze the new sinewave filter design showed much lower voltage distortion (< 2%) as well as other important improvements in performance included a very low insertion loss (ie. < 3% drop in voltage at full load) and improvement in PF to near unity at the inverter output. To complete the study, sinewave filters were built, tested and installed in several wells. Field data was gathered providing power quality measurements for electrical distortion, current imbalance, motor temperatures, motor vibration and production rates. The successful sinewave filter design used different tuned frequency parameters than conventional sinewave filters with clear data providing performance improvement. These results showed a substantial reduction in motor temperature leading to confidence in operations regarding the positive effect this would have on lifecycle of downhole equipment. The improvements can be streamlined across other ESP wells in the field leading to improved runtime, decrease in CAPEX & OPEX cost associated with ESPs and other surface equipment eventually leading to a strong cash flow performance for operators.

Fuses in distribution systems: new applications in DC circuits

The vast majority of distribution systems currently in use, work with alternating current at 50 Hz or 60 Hz. Several of the distributed resources (generators or storage) supply electrical energy in the form of direct current. Also, there are continuous end-use applications such as centralized variable speed drives, and the rapidly growing application in electric cars which has recently started. This panorama leads to the growing interest in the application of fuses in direct current systems, not as an adaptation of the alternating current fuse but as a specific design. The article presents the crucial differences between direct and alternating circuits, oriented to the operation of the fuse, highlighting their advantages and disadvantages, citing the complications in the design that are required for this growing application. The continuous operation of the fuse is explained in its three fundamental parts: pre-arc, arc and post-arc. The most important current applications are analyzed, such as the protection of: circuits with batteries, circuits of electric vehicles for individual use, power electronics, photovoltaic cells, public transport and circuits in mining. It is concluded in the need to deepen the study of these applications in order to achieve specific fuses designs for direct current and not mere adaptations of the traditional alternating current fuse designs.

Analysis of Energy Use and Energy Savings: A Case Study of a Condiment Industry in India

Electric motors and boilers lead the industrial components which consume the largest portion of energy in an industry. This study explores the energy audit data of the condiment industry in India. The study mainly focuses on the estimation of the load factor, energy use, energy savings and annual bill savings with payback period of the electric motors of the plant. During the audit, it was found that there were several motors running under loaded conditions despite non-availability of variable speed drives installed in the plant. Therefore, variable speed drives are recommended to be installed to save energy by reducing the motors speed by up to 60%. According to the estimation, about 276 MWh, 551 MWh and 827 MWh electrical energy can be saved for 20%, 40% and 60% speed reduction of the motors using variable speed drives, respectively, where in most of the cases the payback period remains below 1 year. Furthermore, some suggestions are made to improve the poor power factor of running motors by using capacitor banks to save the reactive power. Besides, an estimation of energy saving is performed with a 2-ton capacity boiler. Since, there was no heat recovery system in the boiler; an air-preheater is suggested to be installed at the end of flue gas exhausting path of the boiler with the purpose of saving 68 tons of fuel per annum and having a payback period of 12 months. Moreover, a digital monitoring system, namely, “The Smart Joules” has been proposed to be installed in the plant aiming at saving about 3–5% of total energy per annum and having a payback period of 19 months. Finally, a summarization is made concluding in the fact that about 90 MWh energy and 95 tons of fuel can be saved (excluding motor energy savings) per annum by implementing proposed measures with a payback period of 15 months.